I used a tapejara to tame a quetzal solo. I added enough stone into my inventory to slow my ride, then hopped in the front seat with a tranq rifle and whistled my tapejara to attack the quetzal. Since it was slowed down, it wasn't able to get close enough to the quetzal to attack it after I started firing. When the quetzal was getting too far away, I dropped some rocks to speed up. It was overall a somewhat tedious process, but in the end it was worth it.